
#include <stdio.h>
#include <string.h>
int main()
{
    int i, len_1, len_2, m;
    char str1[] = "ddsfdsf";
    char str2[] = "dsgjjas";
    len_1 = strlen(str1);
    len_2 = strlen(str2);
    for (i = len_1, m = 0; i < len_1 + len_2 && m < len_2; i++)
        str1[i] = str2[m++];
    printf("%s",str1);
    return 0;
}